US20130034437A1 - Fastening device particularly suitable for the fastening between an air intake and an engine of an aircraft nacelle - Google Patents
Fastening device particularly suitable for the fastening between an air intake and an engine of an aircraft nacelle Download PDFInfo
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- US20130034437A1 US20130034437A1 US13/563,858 US201213563858A US2013034437A1 US 20130034437 A1 US20130034437 A1 US 20130034437A1 US 201213563858 A US201213563858 A US 201213563858A US 2013034437 A1 US2013034437 A1 US 2013034437A1
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- Prior art keywords
- fastening element
- fastening
- annular flange
- rod
- angle profile
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- 238000006073 displacement reaction Methods 0.000 claims description 4
- 210000003414 extremity Anatomy 0.000 description 8
- 230000005465 channeling Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 210000001364 upper extremity Anatomy 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
- B64D2033/0206—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes comprising noise reduction means, e.g. acoustic liners
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
- B64D2033/0266—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes specially adapted for particular type of power plants
- B64D2033/0286—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes specially adapted for particular type of power plants for turbofan engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2240/00—Components
- F05D2240/10—Stators
- F05D2240/14—Casings or housings protecting or supporting assemblies within
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the present invention relates to an aircraft nacelle integrating a fastening device ensuring the connection between an air inlet and an engine, while limiting the propagation of deformations between the two assembled elements, specifically in radial direction.
- An aircraft propulsion assembly comprises a nacelle in which an engine is installed in concentric manner and connected through the intermediary of a post to the rest of the aircraft.
- the nacelle comprises in front an air inlet 10 channeling the air flow in the direction of engine 12 .
- the air inlet has a lip 14 with a surface which is in contact with the aerodynamic flow, and is extended inside the nacelle by an internal conduit 16 and on the outside of the nacelle by an exterior wall 18 .
- the air inlet 10 is connected with the engine 12 by a fastening device illustrated in detail in FIGS. 2 , 3 A and 3 B.
- This fastening device comprises at the engine a first annular flange 20 attached to a second annular flange 22 of a panel delimiting conduit 16 or an intermediate part 24 , called flange, connected to the panel delimiting the conduit 16 , as illustrated in FIG. 2 ,
- the two flanges 20 and 22 are located against each other and held in this position by fastening elements 26 , for instance bolts or rivets, passing through flanges 20 , 22 and extending parallel to the longitudinal axis of the nacelle.
- the bolts or rivets 26 comprise a rod 28 with a diameter which can be adapted to the passage holes made in the annular flanges 20 and 22 .
- the diameter of the passage holes made in annular flanges 20 and 22 can be slightly larger than the diameter of rod 28 of bolts or rivets 26 . This play of approximately 1 mm between the passage holes and the bolts or rivets 26 allows for relative movement between the two connected elements.
- the fastening device and more particularly the bolts or rivets 26 are dimensioned to mitigate any risk of incidents, such as for instance breakage of a blower blade.
- the engine conduit can deform over its whole periphery or part of it. During these deformations, the passage holes of the annular flange of the engine are no longer located in line with the air inlet holes.
- the bolts or rivets 26 are subjected to relatively high shear stresses, which are distinctly higher than the stresses under normal operating conditions. Even if the second implementation mode allows for relative movement between the two connected parts, due to the clearance around the bolts or rivets 26 , this play is markedly smaller than the relative movement between the two connected parts in case of an incident such as breakage of a blade. In the case of the second implementation mode with play, it is observed that the shear stresses are at least equal to the stresses occurring for the first implementation mode, or even greater.
- the fastening device comprises a specific number of bolts or rivets 26 of specific diameter.
- a fastening device must be provided with a large number of bolts or rivets 26 and/or with bolts or rivets 26 of large diameter, which results in higher embarked mass and consequently higher energy consumption of the aircraft.
- a filter can be installed at the location of the fastening elements 26 .
- this filter comprises at least one deformable bushing 30 slipped over rod 28 of fastening element 26 .
- the deformable bushing 30 is inserted between the annular flange 20 attached to the engine and a nut 32 of fastening element 26 .
- This deformable bushing 30 has an inside diameter adapted to the diameter of rod 28 and its central part has a relatively thin wall thickness so that is can deform, particularly through buckling. This arrangement increases the energy absorbed by the fastening device through deformation. It also limits the propagation of deformations in axial direction.
- An embodiment of the present invention proposes a fastening device more particularly suited for connecting an engine and an air inlet of an aircraft nacelle, which limits the propagation of deformations between the two assembled elements, specifically in radial direction.
- An embodiment of the present invention includes aircraft nacelle comprising a first air inlet conduit and a second engine conduit, whereby the two conduits are arranged end to end and connected by a fastening device comprising an annular flange attached to the air inlet and an annular flange attached to the engine and located against said annular flange of the air inlet, said annular flanges are connected by means of a plurality of passage holes, made in the annular flanges and located in line with each other, and first fastening elements of which the rods are housed in the passage holes, characterized in that, for at least one fastening element, the passage hole of one of the annular flanges has a diameter markedly greater than the diameter of the rod, allowing for movement of said rod in case of deformation of one of the two conduits, and in that an angle profile is inserted between the first fastening element and a cylindrical part adjacent to said annular flange, said angle profile is connected to the adjacent cylindrical portion through the intermediary of at least one second
- FIG. 1 is a schematic cross section along a radial plane of the front part of an aircraft nacelle
- FIG. 2 is a view in perspective illustrating a portion of a connection between engine and air inlet of an aircraft nacelle according to prior art
- FIG. 3A is a cross section illustrating a fastening element between engine and air inlet of an aircraft nacelle according to a first implementation mode of prior art
- FIG. 3B is a cross section illustrating a fastening element between engine and air inlet of an aircraft nacelle according to another implementation mode of prior art
- FIG. 4 a is a view in perspective of a portion of a connection between engine and air inlet of an aircraft nacelle according to the invention
- FIG. 4B is a lateral view of the connection portion visible in FIG. 4A after deformation
- FIG. 5A is a cross section of a connection between engine and air inlet of an aircraft nacelle according to a variant of the invention
- FIG. 5B is a cross section of the connection illustrated in FIG. 5A after deformation
- FIG. 6A is a cross section of a connection between engine and air inlet of an aircraft nacelle according to another variant of the invention.
- FIG. 6B is a cross section of the connection illustrated in FIG. 6A after deformation.
- FIGS. 5A , 5 B, 6 A and 6 B show a cross section of the joint zone between a first air inlet conduit 42 and a second engine conduit 44 of an aircraft nacelle, which are arranged end to end.
- the section plane contains the longitudinal axis of the nacelle and the axis of a fastening element.
- the fastening device between the engine and the air inlet comprises on the engine side, an annular flange 46 extending in a plane perpendicular to the longitudinal axis of the nacelle and comprising a plurality of passage holes 48 , on the air inlet side, an annular flange 50 extending in a plane perpendicular to the longitudinal axis of the nacelle, and locating against the annular flange 46 of the engine at the joint plane with reference 52 and comprising a plurality of passage holes 54 , arranged in line with passage holes 48 of the engine, and fastening elements 56 distributed over the periphery of the annular flanges 46 and 50 and housed in the passage holes 48 and 54 .
- each annular flange 46 , 50 is solidly attached to an adjacent cylindrical portion 57 .
- the annular flange can be made in a single piece with the engine or air inlet.
- the annular flange can be an independent piece, assembled to the engine or air inlet.
- the annular flange 50 solidly attached to the air inlet, is made in a single piece with a cylinder portion so as to form a flange with L section in a longitudinal plane, as illustrated in FIG. 4A .
- the annular flange 50 can extend as a single piece along the whole circumference or can consist of several angular sectors as illustrated in FIG. 4A .
- Each fastening element 56 comprises a rod 58 in the form of a cylinder with in a first extremity a first shoulder locating against the free face of one of the flanges, in this case the annular flange 50 of the air inlet, and in the other extremity a second shoulder 62 locating against the free face of the other flange, in this case the annular flange 46 of the engine.
- a fastening element 56 can have the form of a bolt, with on one side a screw consisting of a rod with a head in a first extremity (corresponding to the first shoulder 60 ) and a thread in the other extremity, and on the other side a nut (corresponding to the second shoulder 62 ) which is screwed on the threaded extremity.
- the fastening element can have the form of a rivet with a rod comprising in a first extremity a head forming the first shoulder and a second shoulder in the second extremity obtained by deformation of the second extremity.
- the fastening element 56 comprises a deformable bushing 64 which can be slipped over rod 58 and interposed between one of the flanges and one of the shoulders.
- the deformable bushing 64 is inserted between the annular flange 46 of the engine and shoulder 62 consisting of a nut of the fastening element,
- This deformable bushing 64 has an inside diameter adapted to the diameter of rod 58 and comprises in the central part a relatively thin wall thickness so that it can deform, particularly through buckling.
- the arrangement increases the energy absorbed by deformation of the fastening device and limits the propagation of deformations oriented in axial direction.
- An embodiment of the invention further proposes a fastening device that absorbs through plastic and elastic deformation a portion of the energy produced by the impact of a blade fragment against the engine conduit and is limiting the propagation of deformations, more particularly the radial deformations, between the engine conduit and the air inlet conduit.
- fastening element 56 Although it is described for one fastening element, it applies at least to one fastening element 56 and by preference to all fastening elements 56 .
- the passage hole 48 of the annular flange 46 solidly attached to the engine, has a diameter adapted to the diameter of rod 58 of fastening element 56 .
- the relative movement between the fastening element 56 and the annular flange 46 is almost zero.
- adapted we mean that the clearance between the passage hole 48 and the rod is smaller than or equal to 2 mm.
- the diameter of passage hole 54 in the annular flange 50 is distinctly greater than the diameter of rod 58 so as to allow for a displacement of said rod 58 greater than or equal to 5 mm.
- the axis of passage hole 54 is offset towards the exterior relative to the axis of the passage hole 48 in order to obtain the longest travel, knowing that rod 60 will move radially towards the exterior in case of blade breakage.
- the portion of the circumference of passage hole 54 closest to the longitudinal axis of the nacelle is at the same height as the corresponding portion of the circumference of passage hole 48
- the portion of the circumference of passage hole 54 the farthest away from the longitudinal axis of the nacelle is offset towards the exterior relative to the corresponding portion of the circumference of passage hole 48 .
- an angle profile 66 is inserted between the fastening element 56 and the cylindrical portion 57 adjacent to the annular flange 50 , said angle profile 66 is connected to the adjacent cylindrical portion 57 through the intermediary of at least one fastening element 68 , suitable for absorbing eventual deformations in radial direction.
- the angle profile 66 has an L section in a longitudinal plane and comprises a first wing 70 located against the annular flange 50 and another wing 72 located against the adjacent cylindrical portion 57 , which corresponds in this case to a tubular part with a flange.
- the first wing 70 comprises a passage hole 74 with a diameter adapted to the diameter of rod 58 of fastening element 56 . In this way, the relative movement between the fastening element 56 and the angle profile 66 is almost zero.
- the second wing 72 is connected to the adjacent cylindrical portion 57 through the intermediary of at least one fastening element 68 .
- two identical fastening elements 68 can be provided for connecting the angle profile 66 to the adjacent cylindrical portion 57 as illustrated in FIG. 4A .
- connection When a blade breaks, the connection may be subjected to stresses that are not purely radial and can have a component in tangential direction due to the rotational speed of the blades.
- the arrangement with two fastening elements 68 absorbs also eventual deformations in tangential direction thanks to dissymmetric deformation of the fastening elements 68 as illustrated in FIG. 4B .
- the angle profile 66 In the presence of two fastening elements 68 , the angle profile 66 has a triangular shape with rounded tops when it is unfolded and flattened.
- the fastening element 68 comprises a rod 76 , with axis oriented in radial direction, fixed relative to the air inlet and the annular flange 50 with in its upper extremity a shoulder 78 in the form, for instance, of a screw head or a nut.
- the second wing 72 comprises a passage hole for rod 76 with a hole diameter which may or may not be adapted to the diameter of rod 76 .
- a deformable element 80 is inserted between the shoulder 78 and the second wing 72 of the angle profile.
- the deformable element 80 can be a deformable bushing functioning in the same manner as deformable bushing 64 .
- the engine conduit has a tendency to deform in radial direction. This radial deformation provokes a radial movement towards the exterior of the fastening element 56 . Since the diameter of passage hole 74 of angle profile 66 is adapted to the diameter of the rod of fastening element 56 , the angle profile 66 follows the radial movement towards the exterior of fastening element 56 .
- deformable element 80 absorbs a portion of the energy, which tends to limit the movement of rod 58 of fastening element 56 so that in this way it is not subjected to shear stresses by coming in contact with the wall of passage hole 54 .
- the invention is not limited to the deformable bushing as illustrated in the figures.
- the deformable element could consist of a compression spring.
- the deformable element 80 will generate a force with a tendency of opposing the radial movement towards the exterior of the angle profile and therefore of fastening element 56 .
- This force is proportional to the radial displacement ⁇ of the fastening element.
- the bushing height is inversely proportional to the distance separating fastening element 68 from the first wing 70 of angle profile 66 .
- the angle profile 66 when deforming, more particularly when deforming by unfolding, can absorb a portion of the deformation energy and limit the radial movement of fastening element 56 as illustrated in FIG. 6B .
- deformable element 80 is subjected to a deformation which is smaller than the deformation to which this same element would be subjected in the configurations of FIGS. 5A and 5B , so that the height of the deformable element 80 can be smaller than the height of the same element in the configurations of FIGS. 5A and 5B .
- the deformable element when the distance separating fastening element 68 and the first wing 70 of the angle profile varies from 5 to 15 mm, the deformable element must have a height allowing for a travel of 10 mm.
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Abstract
Description
- The present invention relates to an aircraft nacelle integrating a fastening device ensuring the connection between an air inlet and an engine, while limiting the propagation of deformations between the two assembled elements, specifically in radial direction.
- An aircraft propulsion assembly comprises a nacelle in which an engine is installed in concentric manner and connected through the intermediary of a post to the rest of the aircraft.
- As illustrated in
FIG. 1 , the nacelle comprises in front anair inlet 10 channeling the air flow in the direction ofengine 12. - The air inlet has a
lip 14 with a surface which is in contact with the aerodynamic flow, and is extended inside the nacelle by aninternal conduit 16 and on the outside of the nacelle by anexterior wall 18. - The
air inlet 10 is connected with theengine 12 by a fastening device illustrated in detail inFIGS. 2 , 3A and 3B. This fastening device comprises at the engine a firstannular flange 20 attached to a secondannular flange 22 of apanel delimiting conduit 16 or anintermediate part 24, called flange, connected to the panel delimiting theconduit 16, as illustrated inFIG. 2 , The twoflanges fastening elements 26, for instance bolts or rivets, passing throughflanges - According to an implementation mode illustrated in
FIG. 3A , the bolts orrivets 26 comprise arod 28 with a diameter which can be adapted to the passage holes made in theannular flanges - According to a second implementation mode illustrated in
FIG. 3B , the diameter of the passage holes made inannular flanges rod 28 of bolts orrivets 26. This play of approximately 1 mm between the passage holes and the bolts orrivets 26 allows for relative movement between the two connected elements. - In both cases the passage holes are cylindrical.
- The fastening device and more particularly the bolts or
rivets 26 are dimensioned to mitigate any risk of incidents, such as for instance breakage of a blower blade. - In this case, the engine conduit can deform over its whole periphery or part of it. During these deformations, the passage holes of the annular flange of the engine are no longer located in line with the air inlet holes. In this configuration, the bolts or
rivets 26 are subjected to relatively high shear stresses, which are distinctly higher than the stresses under normal operating conditions. Even if the second implementation mode allows for relative movement between the two connected parts, due to the clearance around the bolts or rivets 26, this play is markedly smaller than the relative movement between the two connected parts in case of an incident such as breakage of a blade. In the case of the second implementation mode with play, it is observed that the shear stresses are at least equal to the stresses occurring for the first implementation mode, or even greater. - To withstand these stresses, the fastening device comprises a specific number of bolts or
rivets 26 of specific diameter. - Taking into account the strength of a bolt or rivet 26 in an assembly according to the implementation modes illustrated in
FIGS. 3A and 3B , a fastening device must be provided with a large number of bolts orrivets 26 and/or with bolts orrivets 26 of large diameter, which results in higher embarked mass and consequently higher energy consumption of the aircraft. - Another problem is that the deformations of the engine conduit have a tendency to propagate in the direction of
air inlet conduit 16. Consequently, it is necessary to take into account these possible deformations during the design of theair inlet conduit 16 which is made, in general, of composite material and integrates and acoustic treatment system. - To limit the propagation of deformations from
annular flange 20 of the engine towardsflange 22 of the air inlet, a filter can be installed at the location of thefastening elements 26. For each connection device, this filter comprises at least one deformable bushing 30 slipped overrod 28 offastening element 26. According to the example illustrated inFIG. 3A , thedeformable bushing 30 is inserted between theannular flange 20 attached to the engine and anut 32 offastening element 26. Thisdeformable bushing 30 has an inside diameter adapted to the diameter ofrod 28 and its central part has a relatively thin wall thickness so that is can deform, particularly through buckling. This arrangement increases the energy absorbed by the fastening device through deformation. It also limits the propagation of deformations in axial direction. - However, in case of blade breakage, the most important deformations are oriented in radial direction. In this direction, the effects of the
deformable bushing 30 are limited. - An embodiment of the present invention proposes a fastening device more particularly suited for connecting an engine and an air inlet of an aircraft nacelle, which limits the propagation of deformations between the two assembled elements, specifically in radial direction.
- An embodiment of the present invention includes aircraft nacelle comprising a first air inlet conduit and a second engine conduit, whereby the two conduits are arranged end to end and connected by a fastening device comprising an annular flange attached to the air inlet and an annular flange attached to the engine and located against said annular flange of the air inlet, said annular flanges are connected by means of a plurality of passage holes, made in the annular flanges and located in line with each other, and first fastening elements of which the rods are housed in the passage holes, characterized in that, for at least one fastening element, the passage hole of one of the annular flanges has a diameter markedly greater than the diameter of the rod, allowing for movement of said rod in case of deformation of one of the two conduits, and in that an angle profile is inserted between the first fastening element and a cylindrical part adjacent to said annular flange, said angle profile is connected to the adjacent cylindrical portion through the intermediary of at least one second fastening element comprising a means for absorbing eventual deformations in radial direction.
- Other characteristics and advantages will become clear from the following description of the invention, which is given only as an example, with respect to the attached drawings in which:
-
FIG. 1 is a schematic cross section along a radial plane of the front part of an aircraft nacelle, -
FIG. 2 is a view in perspective illustrating a portion of a connection between engine and air inlet of an aircraft nacelle according to prior art, -
FIG. 3A is a cross section illustrating a fastening element between engine and air inlet of an aircraft nacelle according to a first implementation mode of prior art, -
FIG. 3B is a cross section illustrating a fastening element between engine and air inlet of an aircraft nacelle according to another implementation mode of prior art, -
FIG. 4 a is a view in perspective of a portion of a connection between engine and air inlet of an aircraft nacelle according to the invention, -
FIG. 4B is a lateral view of the connection portion visible inFIG. 4A after deformation, -
FIG. 5A is a cross section of a connection between engine and air inlet of an aircraft nacelle according to a variant of the invention, -
FIG. 5B is a cross section of the connection illustrated inFIG. 5A after deformation, -
FIG. 6A is a cross section of a connection between engine and air inlet of an aircraft nacelle according to another variant of the invention, and -
FIG. 6B is a cross section of the connection illustrated inFIG. 6A after deformation. -
FIGS. 5A , 5B, 6A and 6B show a cross section of the joint zone between a firstair inlet conduit 42 and asecond engine conduit 44 of an aircraft nacelle, which are arranged end to end. The section plane contains the longitudinal axis of the nacelle and the axis of a fastening element. - According to one implementation mode, the fastening device between the engine and the air inlet comprises on the engine side, an
annular flange 46 extending in a plane perpendicular to the longitudinal axis of the nacelle and comprising a plurality ofpassage holes 48, on the air inlet side, anannular flange 50 extending in a plane perpendicular to the longitudinal axis of the nacelle, and locating against theannular flange 46 of the engine at the joint plane withreference 52 and comprising a plurality ofpassage holes 54, arranged in line withpassage holes 48 of the engine, andfastening elements 56 distributed over the periphery of theannular flanges passage holes - In all cases, each
annular flange cylindrical portion 57. - According to one implementation mode, the annular flange can be made in a single piece with the engine or air inlet. In variant, the annular flange can be an independent piece, assembled to the engine or air inlet.
- According to another implementation mode, the
annular flange 50, solidly attached to the air inlet, is made in a single piece with a cylinder portion so as to form a flange with L section in a longitudinal plane, as illustrated inFIG. 4A . In the same manner, theannular flange 50 can extend as a single piece along the whole circumference or can consist of several angular sectors as illustrated inFIG. 4A . - Each
fastening element 56 comprises arod 58 in the form of a cylinder with in a first extremity a first shoulder locating against the free face of one of the flanges, in this case theannular flange 50 of the air inlet, and in the other extremity asecond shoulder 62 locating against the free face of the other flange, in this case theannular flange 46 of the engine. - According to one implementation mode, a
fastening element 56 can have the form of a bolt, with on one side a screw consisting of a rod with a head in a first extremity (corresponding to the first shoulder 60) and a thread in the other extremity, and on the other side a nut (corresponding to the second shoulder 62) which is screwed on the threaded extremity. - In variant, the fastening element can have the form of a rivet with a rod comprising in a first extremity a head forming the first shoulder and a second shoulder in the second extremity obtained by deformation of the second extremity.
- Advantageously, the
fastening element 56 comprises adeformable bushing 64 which can be slipped overrod 58 and interposed between one of the flanges and one of the shoulders. According to the illustrated example, thedeformable bushing 64 is inserted between theannular flange 46 of the engine andshoulder 62 consisting of a nut of the fastening element, Thisdeformable bushing 64 has an inside diameter adapted to the diameter ofrod 58 and comprises in the central part a relatively thin wall thickness so that it can deform, particularly through buckling. The arrangement increases the energy absorbed by deformation of the fastening device and limits the propagation of deformations oriented in axial direction. - An embodiment of the invention further proposes a fastening device that absorbs through plastic and elastic deformation a portion of the energy produced by the impact of a blade fragment against the engine conduit and is limiting the propagation of deformations, more particularly the radial deformations, between the engine conduit and the air inlet conduit.
- The specific arrangement of the embodiment is described as applied to the
annular flange 50 solidly attached to the air inlet. It can be applied also to theannular flange 46 solidly attached to the engine. - Although it is described for one fastening element, it applies at least to one
fastening element 56 and by preference to allfastening elements 56. - According to an embodiment of the invention, the
passage hole 48 of theannular flange 46, solidly attached to the engine, has a diameter adapted to the diameter ofrod 58 offastening element 56. In this way, the relative movement between thefastening element 56 and theannular flange 46 is almost zero. By “adapted” we mean that the clearance between thepassage hole 48 and the rod is smaller than or equal to 2 mm. - In parallel, the diameter of
passage hole 54 in theannular flange 50 is distinctly greater than the diameter ofrod 58 so as to allow for a displacement of saidrod 58 greater than or equal to 5 mm. - Advantageously, the axis of
passage hole 54 is offset towards the exterior relative to the axis of thepassage hole 48 in order to obtain the longest travel, knowing thatrod 60 will move radially towards the exterior in case of blade breakage. In the absence of deformation, as illustrated inFIGS. 5A and 6A , the portion of the circumference ofpassage hole 54 closest to the longitudinal axis of the nacelle is at the same height as the corresponding portion of the circumference ofpassage hole 48, while the portion of the circumference ofpassage hole 54 the farthest away from the longitudinal axis of the nacelle is offset towards the exterior relative to the corresponding portion of the circumference ofpassage hole 48. - According to an embodiment of the invention, an
angle profile 66 is inserted between thefastening element 56 and thecylindrical portion 57 adjacent to theannular flange 50, saidangle profile 66 is connected to the adjacentcylindrical portion 57 through the intermediary of at least onefastening element 68, suitable for absorbing eventual deformations in radial direction. - According to one implementation mode, the
angle profile 66 has an L section in a longitudinal plane and comprises afirst wing 70 located against theannular flange 50 and anotherwing 72 located against the adjacentcylindrical portion 57, which corresponds in this case to a tubular part with a flange. - The
first wing 70 comprises apassage hole 74 with a diameter adapted to the diameter ofrod 58 offastening element 56. In this way, the relative movement between thefastening element 56 and theangle profile 66 is almost zero. - The
second wing 72 is connected to the adjacentcylindrical portion 57 through the intermediary of at least onefastening element 68. Advantageously, twoidentical fastening elements 68 can be provided for connecting theangle profile 66 to the adjacentcylindrical portion 57 as illustrated inFIG. 4A . - When a blade breaks, the connection may be subjected to stresses that are not purely radial and can have a component in tangential direction due to the rotational speed of the blades. The arrangement with two
fastening elements 68 absorbs also eventual deformations in tangential direction thanks to dissymmetric deformation of thefastening elements 68 as illustrated inFIG. 4B . - In the presence of two
fastening elements 68, theangle profile 66 has a triangular shape with rounded tops when it is unfolded and flattened. - According to one implementation mode, the
fastening element 68 comprises arod 76, with axis oriented in radial direction, fixed relative to the air inlet and theannular flange 50 with in its upper extremity ashoulder 78 in the form, for instance, of a screw head or a nut. - The
second wing 72 comprises a passage hole forrod 76 with a hole diameter which may or may not be adapted to the diameter ofrod 76. - According to one aspect of the invention, a
deformable element 80 is inserted between theshoulder 78 and thesecond wing 72 of the angle profile. - According to one implementation mode, the
deformable element 80 can be a deformable bushing functioning in the same manner asdeformable bushing 64. - In case of blade breakage, the engine conduit has a tendency to deform in radial direction. This radial deformation provokes a radial movement towards the exterior of the
fastening element 56. Since the diameter ofpassage hole 74 ofangle profile 66 is adapted to the diameter of the rod offastening element 56, theangle profile 66 follows the radial movement towards the exterior offastening element 56. - Taking into account the large diameter of
passage hole 54 in theannular flange 50, the radial movement towards the exterior of thefastening element 56 is not transmitted to theflange 50 and therefore is not transmitted to the air inlet. - As illustrated in
FIGS. 5B and 6B , while deforming,deformable element 80 absorbs a portion of the energy, which tends to limit the movement ofrod 58 offastening element 56 so that in this way it is not subjected to shear stresses by coming in contact with the wall ofpassage hole 54. - With this arrangement, the propagation of radial deformations towards the air inlet is limited.
- The invention is not limited to the deformable bushing as illustrated in the figures. For instance, the deformable element could consist of a compression spring.
- According to an embodiment of the invention, the
deformable element 80 will generate a force with a tendency of opposing the radial movement towards the exterior of the angle profile and therefore offastening element 56. This force is proportional to the radial displacement Δ of the fastening element. - When the deformable element is a deformable bushing as illustrated in
FIGS. 5A , 5B, 6A and 6B, the bushing height is inversely proportional to the distance separatingfastening element 68 from thefirst wing 70 ofangle profile 66. In fact, when fasteningelement 68 is located at a distance from thefirst wing 70 as illustrated inFIGS. 6A and 6B , theangle profile 66, when deforming, more particularly when deforming by unfolding, can absorb a portion of the deformation energy and limit the radial movement offastening element 56 as illustrated inFIG. 6B . In this case,deformable element 80 is subjected to a deformation which is smaller than the deformation to which this same element would be subjected in the configurations ofFIGS. 5A and 5B , so that the height of thedeformable element 80 can be smaller than the height of the same element in the configurations ofFIGS. 5A and 5B . - As an example, when the distance separating
fastening element 68 and thefirst wing 70 of the angle profile varies from 5 to 15 mm, the deformable element must have a height allowing for a travel of 10 mm.
Claims (10)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1157203 | 2011-08-05 | ||
FR1157203A FR2978735A1 (en) | 2011-08-05 | 2011-08-05 | CONNECTION DEVICE PARTICULARLY ADAPTED TO ENSURE THE CONNECTION BETWEEN AN AIR INLET AND A MOTORIZATION OF AN AIRCRAFT NACELLE |
Publications (2)
Publication Number | Publication Date |
---|---|
US20130034437A1 true US20130034437A1 (en) | 2013-02-07 |
US9315275B2 US9315275B2 (en) | 2016-04-19 |
Family
ID=46603849
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/563,858 Active 2035-01-17 US9315275B2 (en) | 2011-08-05 | 2012-08-01 | Fastening device particularly suitable for the fastening between an air intake and an engine of an aircraft nacelle |
Country Status (3)
Country | Link |
---|---|
US (1) | US9315275B2 (en) |
EP (1) | EP2554481B1 (en) |
FR (1) | FR2978735A1 (en) |
Cited By (4)
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US20140321999A1 (en) * | 2013-04-26 | 2014-10-30 | Snecma | Turbine engine casing |
US9643651B2 (en) | 2015-08-28 | 2017-05-09 | Honda Motor Co., Ltd. | Casting, hollow interconnecting member for connecting vehicular frame members, and vehicular frame assembly including hollow interconnecting member |
FR3045113A1 (en) * | 2015-12-11 | 2017-06-16 | Snecma | METHOD OF ASSEMBLING TWO ANNULAR PIECES |
US10233837B2 (en) * | 2015-03-16 | 2019-03-19 | Snecma | Assembly for an aircraft turbine engine comprising a fan casing equipped with an acoustic liner incorporating a fan casing stiffener |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2975970B1 (en) * | 2011-05-30 | 2013-05-17 | Aircelle Sa | TOGETHER FOR AN AIRCRAFT NACELLE |
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US20050053419A1 (en) * | 2003-09-09 | 2005-03-10 | Mcmillan Alison J. | Joint arrangement |
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FR2767560B1 (en) * | 1997-08-19 | 1999-11-12 | Aerospatiale | NOISE REDUCTION ASSEMBLY FOR AN AIRCRAFT TURBOREACTOR |
US7056053B2 (en) * | 2002-11-27 | 2006-06-06 | General Electric Company | Bolting arrangement including a two-piece washer for minimizing bolt bending |
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- 2011-08-05 FR FR1157203A patent/FR2978735A1/en not_active Withdrawn
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- 2012-07-31 EP EP12305939.6A patent/EP2554481B1/en active Active
- 2012-08-01 US US13/563,858 patent/US9315275B2/en active Active
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US20040033133A1 (en) * | 2002-08-15 | 2004-02-19 | General Electric Company | Compressor bleed case |
US20050053419A1 (en) * | 2003-09-09 | 2005-03-10 | Mcmillan Alison J. | Joint arrangement |
US20050252195A1 (en) * | 2004-04-27 | 2005-11-17 | Airbus France | Noise reduction assembly for aircraft turbojet |
WO2008006959A1 (en) * | 2006-07-12 | 2008-01-17 | Airbus France | Air intake for an aircraft turbine engine |
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US20140321999A1 (en) * | 2013-04-26 | 2014-10-30 | Snecma | Turbine engine casing |
US9611863B2 (en) * | 2013-04-26 | 2017-04-04 | Snecma | Turbine engine casing |
US10233837B2 (en) * | 2015-03-16 | 2019-03-19 | Snecma | Assembly for an aircraft turbine engine comprising a fan casing equipped with an acoustic liner incorporating a fan casing stiffener |
US9643651B2 (en) | 2015-08-28 | 2017-05-09 | Honda Motor Co., Ltd. | Casting, hollow interconnecting member for connecting vehicular frame members, and vehicular frame assembly including hollow interconnecting member |
US10647358B2 (en) | 2015-08-28 | 2020-05-12 | Honda Motor Co., Ltd. | Casting, hollow interconnecting member for connecting vehicular frame members, and vehicular frame assembly including hollow interconnecting member |
US11358644B2 (en) | 2015-08-28 | 2022-06-14 | Honda Motor Co., Ltd. | Casting, hollow interconnecting member for connecting vehicular frame members, and vehicular frame assembly including hollow interconnecting member |
FR3045113A1 (en) * | 2015-12-11 | 2017-06-16 | Snecma | METHOD OF ASSEMBLING TWO ANNULAR PIECES |
Also Published As
Publication number | Publication date |
---|---|
US9315275B2 (en) | 2016-04-19 |
EP2554481A3 (en) | 2014-07-02 |
EP2554481B1 (en) | 2015-10-14 |
EP2554481A2 (en) | 2013-02-06 |
FR2978735A1 (en) | 2013-02-08 |
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